Known engines include a generator-equipped engine into which a generator is incorporated. The generator is composed of a stator that is fixed to the crankcase, and a rotor that is capable of rotating. The rotor is composed of a flywheel attached to the crankshaft, and a plurality of magnets provided to the flywheel. The plurality of magnets are arranged in the radial direction of the flywheel.
The following process is an example of the procedure for assembling a generator-equipped engine. First, the stator is attached to the crankcase. A piston is then connected to the crankshaft via a connecting rod. Then, the flywheel is mounted on the crankshaft while the piston is positioned at the top-dead-center point. The generator is thereby incorporated into the engine.
When the stator and the magnets are assembled together, a magnetic force occurs between the stator and the magnets. In other words, cogging (magnetic attraction) occurs between the iron cores of the stator and the magnetic poles of the rotor.
When an engine is built or serviced, the piston must be maintained in the top-dead-center position. However, the effects of cogging tend to make it difficult to position the piston near the top-dead-center point. In other words, when the magnetic force that occurs is unstable, this magnetic force causes the flywheel to rotate. When the flywheel rotates, the crankshaft rotates, and the piston moves away from the top-dead-center point. The flywheel must therefore be prevented from rotating about the crankshaft due to the magnetic force during mounting of the flywheel on the crankshaft, thus adding labor to the engine assembly process.
A technique is therefore desired that can facilitate the work of assembling a generator-equipped engine.
A kick-starting engine for a two-wheeled automobile is described in Japanese Laid-open Patent Application No. 62-203973 as another engine technique. In order to facilitate kick-starting in the engine described in Japanese Laid-open Patent Application No. 62-203973, the engine is configured so that it can easily be detected whether the piston is near the top-dead-center position, which is optimal for kick starting. However, the assembly process is difficult to facilitate even when this type of technique is applied in a generator-equipped engine.